Square in a square math is making my head hurt
 

I want to make a quilt that combines square in a square blocks like this one:

http://www.google.com/imgres?imgurl=...Q9QEwBg&dur=62

The small blocks are a square in a square. The larger blocks are a square in a square in a square. If I want my small blocks to finish at 4 inches then the larger block has to finish at 8 inches. I can't figure out the math on the larger square. Can someone with experience give me the dimentions of the inside square, and the squares I would need to make the corners of the 2 "outside squares"?

Hi, I used my EQ7 software to figure this out:

-inside square is 4-1/2 inch square

- middle square is one 5-2/16 square cut into four pieces on the diagonal

- outside square is two 4-7/8 square - each square is cut into two pieces on the diagonal

I hope that helps. Let me know if you would like pictures to further explain.

Thanks Judy. I will have to try this. I like having a little extra room to square off so that there is exactly a quarter inch beyond the "point" so I will probably add a 1/4 inch or so to your middle and outside square measurements. I really appreciate you going to the trouble to figure this out for me!! I have a lot of blue batiks and think this would be really pretty with those.

You're welcome. I think it will look stunning in blue batiks. It is a handsome quilt. I can see why you want to make it.

I bought the Deb Tucker square-in-square ruler, love it.

Someone recently posted that you cut a square 1-1/4" bigger than the finished size of the inner square, and then cut diagonally into four triangles. Means sewing on the bias, but it can't be helped. I haven't tried this yet, but plan to.